Icons for Component menu items

I would like to have icons for the menu items for my component. I have tried the following (yes I do have these icons defined in my resources). When I expand my component to see my menu items, the Text (second parameter) appears, and the function call (3rd parameter) works properly, but the icon is not present. Do I need a different size?

protected override void AppendAdditionalComponentMenuItems(ToolStripDropDown menu) 
{
  base.AppendAdditionalComponentMenuItems(menu);

  Menu_AppendItem(menu, "Sign In", Account, null, new Bitmap(Properties.Resources.SignIn, 24, 24));
  Menu_AppendItem(menu, "Settings", Settings, null, new Bitmap(Properties.Resources.Settings, 24, 24));
  Menu_AppendItem(menu, "Help", Help, null, new Bitmap(Properties.Resources.Help, 24, 24));
  Menu_AppendItem(menu, "About", About, null, new Bitmap(Properties.Resources.About, 24, 24));
}

From the following:
https://developer.rhino3d.com/api/grasshopper/html/Overload_Grasshopper_Kernel_GH_DocumentObject_Menu_AppendItem.htm

Menu_AppendItem(ToolStrip, String, EventHandler, Image)
Toolstrip is menu
“Sign In” is string,
Account is event handler.
your bitmap is your image.

So there shouldn’t be a null there.

Thanks, I was off by one! (parameter)